Excess Moisture Injury of Soybeans Cultivated in a Upland Field Converted from Paddy : II. Effects of excessive soil moisture on bleeding, stomatal aperture and mineral absorption

Using the same materials as reported in the previous paper, effects of excessive soil moisture on bleeding, stomatal aperture and mineral absorption of soybeans (c.v. Tamahomare) were studied. The earlier the growth stage was, the greater were the effects of excessive soil moisture on bleeding, stomatal aperture and mineral absorption. Soybeans were damaged not only by excess moisture but also by drought when they were grown under excessive soil condition followed by insufficient precipitation at the early growth stage when the plant community was not well developed such as at the early stage of flower-bud differentiation. This was because new roots which emerged during the treatment were damaged. Therefore, sufficient precautions must be taken against excess moisture injury at the early growth period, and in case drought damage is predicted, irrigation seems to be an effective practice.